Radios vary, diagrams not matching

[Elizabetty]

Hello. I'm sorry because I really thought this was one I was going to be able to handle myself but this absolutely has turned out to be the most difficult part yet. May03lt did an explanation video on going over RPO codes and looking over the vehicle to determine radio information so I started with him and went from there.

I'm having a very difficult time determining my correct radio wiring though. I have been through this and trailvoy as well as many other sites looking through resources to match and I can't find what I need. I have a 2002 wiring download from someone on this site but none of the diagrams match because I do not have premium sound or steering wheel controls on the base radio diagram.

My RPO for radio is UN0.
I do not have bose.
I do not have rear seat audio control.
I do not have onstar.
I do not have steering wheel controls.

I have the original radio, 15169545, and I have problems with rear speakers as well as in and out static with occasional engine noise. I happened to have the dash out today looking for other things so I thought I would take a peek at the radio because I thought I would have to replace a light bulb in it. Passenger side light doesn't work behind a lot of the buttons.

There is a coax for my antenna.
There is a 24 pin connector.
There is a 12 pin connector. This connector is my confusion. There are three wires. One is bare. The strands of metal are not tight together and in my mind I was thinking these should be twisted or touching each other at least. I decided to do some googling.

I cannot determine what this 12 pin connector is for. I have not been able to find diagrams that match my vehicle specifics. The closest I could come to figuring out anything was that the bare wire is called a drain wire and is a version of a ground. If that's the case, that even more makes me think those bare wires should be twisted together more tightly than what they are, but maybe not.

While googling, I've come across things saying to tape it off because it's for OnStar. That would not surprise me since I seem to have a fuse box in the rear set up for OnStar as well. However, I don't have any indicators anywhere else on the vehicle then there is OnStar. I found other information that said it was to help when there is an amp installed but I have the base radio as far as I can tell from my research.

What the heck is this thing and should it be plugged into my radio? If so, what are the two wires that accompany the drain wire for? I'm working by flashlight as usual with my old lady eyes LOL and unfortunately I can't pull the wires very far forward but it looks like one is brown and the other is black or gray with a white stripe? Don't hold me to those colors. It's really difficult for me to get up close and see. In the end, it's going to be some type of wiring schematic that's going to be most helpful anyway if someone can help me pin one down for my particular setup.

 

[TJBaker57]

See if this matches up.....

 

[TJBaker57]

I don't have any 2003 diagrams and as you found none of the 2002 diagrams have the pin count to match yours.

I was thinking your 2002 may be a late year model amd may have an 03 setup.

 

[TJBaker57]

 

[Elizabetty]

Close but no cigar.

No amp, no vcim cuz no OnStar (from what I could tell, that would be the function through radio having to do with phone calls). Even if rest could still apply, colors don't match pinout. The one in the 2002 wiring I have is close too but not quite. I'm going to keep digging. If I were to buy a Haynes manual, would that possibly have accurate information?

 

[TJBaker57]

Do you happen to have UEI rpo code? edit: ooops... UE1

 

[TJBaker57]

Seen this page yet? It is where I grabbed that last image from.

Radio Wiring Diagram Needed: Hi, I Am Looking for a Car Side Radio...

Hi, I am looking for a car side radio wiring diagram for the vehicle listed above LT 4x4 with OnStar and base radio with rear radio. Also, and advice ...

www.2carpros.com

 

[mrrsm]

Look these over and observe their Bi-Color Wiring Patterns as a comparison from what is on the Diagrams vs. whatever yours looks like:

 

[Elizabetty]

Basically I'm combining and figuring it out. Radio will likely be replaced so this is back burner but can be considered solved I suppose. I have enough info from these pics to at least move forward. It helps to know that with optional features you sometimes get set up for an optional feature that isn't used such as OnStar so I'm making sense of it.

 

[Elizabetty]

After piecing together what I could, it came down to the radio potentially being bad. Perhaps not majorly in any way but I find it annoying that the lights don't all work and sometimes the CD player makes noises when it's not playing anything as if it might be spinning and sometimes the CD seems to spend way too fast for lack of a better way to explain it. I decided since I didn't give up on the truck that I would like to replace the radio and I'm aware of the locked radio problem and then the unlock procedure causing a loss of memory functions etc. I saw the information about the VIN issue, data bus line etc, and dealerships should be able to help but some seem to be clueless. I know I could go aftermarket and use the adapters, and I apologize if that's the wrong word, but there are additional components and/or steps to help it work with the class ii communications.

Unfortunately, I don't see a lot of smooth transitions into an aftermarket radio even when using compatible harness and wiring the way it needs to be with the whole data bus situation.

Also, if I decide to go with the original, they're not cheap but occasionally I see a heck of a deal used somewhere.

1: if the radio keeps freaking out and I decide to remove it entirely, how does that affect all of my communications?
2: is there a way to use an aftermarket radio and truly have full functionality of the vehicle still with the class 2 communications?
3: if replacing with a used one, is there a way to have full functionality as far as saving presets, door chimes and data bus?

Since I am learning as I go, I don't want to create other troubleshooting issues so I'm wondering what my best workaround is to avoid a radio that does what it wants occasionally but still allowing the class ii communications to function correctly.

 

[mrrsm]

If YOU are NOT the Original Owner of the Trailblazer... it is important to know that during its early life as a "Family Vehicle"... Kids can often ride in the Front Passenger Seat and slyly and very creatively ***Drop Coins, Bobby Pins and Paper Clips *** ...OR YOU NAME IT right down inside of the CD Tray Slot. Conductive Metallic Items can naturally cause the Radio To Short the Network to Ground... or even Short to B+ 12 Volts DC Power!

Pull the Radio from the Dash Panel and give it a Very GENTLE *Shake Test*. If you hear anything rattling around inside ... Pull the Front Cover off of the CD Player and DUMP out whatever these Bored Munchkins may have slipped or dropped into that 'Dashboard One Armed Bandit'. You never know... You might just get *LUCKY* and... *DING-DING-DING* ...Come out with a Winner!

Bonus Round...

Drop in on THIS Thread for LOTS of Good Info and Diagrams on Bench Top Harnesses; including How to Make one for The PCM AND The Radio:

SOLVED! - How to Make A "GYMKO" Tech 2 Bench-Top Test Harness

BIGGER EDIT: 04/24/2019 For THE BEST On Topic Solution ...Go Directly to Post # 42... BIG EDIT: This Thread originally was to cover creating a Test Harness to use exclusively for diagnosing and repairing the GM Trailblazer and Envoy, etc Instrument Panel Cluster and Components... but...

gmtnation.com

 

[Elizabetty]

If YOU are NOT the Original Owner of the Trailblazer... it is important to know that during its early life as a "Family Vehicle"... Kids can often ride in the Front Passenger Seat and slyly and very creatively ***Drop Coins, Bobby Pins and Paper Clips *** ...OR YOU NAME IT right down inside of the CD Tray Slot. Conductive Metallic Items can naturally cause the Radio To Short the Network to Ground... or even Short to B+ 12 Volts DC Power!

Pull the Radio from the Dash Panel and give it a Very GENTLE *Shake Test*. If you hear anything rattling around inside ... Pull the Front Cover off of the CD Player and DUMP out whatever these Bored Munchkins may have slipped or dropped into that 'Dashboard One Armed Bandit'. You never know... You might just get *LUCKY* and... *DING-DING-DING* ...Come out with a Winner!

Bonus Round...

Drop in on THIS Thread for LOTS of Good Info and Diagrams on Bench Top Harnesses; including How to Make one for The PCM AND The Radio:

SOLVED! - How to Make A "GYMKO" Tech 2 Bench-Top Test Harness

BIGGER EDIT: 04/24/2019 For THE BEST On Topic Solution ...Go Directly to Post # 42... BIG EDIT: This Thread originally was to cover creating a Test Harness to use exclusively for diagnosing and repairing the GM Trailblazer and Envoy, etc Instrument Panel Cluster and Components... but...

gmtnation.com

Thank you. I have had the entire dash out and the radio. I didn't hear anything when I shook it. Everything seems to work on it other than the rear speakers but I haven't taken the rear door panels off yet and that's my last step there. I wish there was something in the CD player LOL would be nice to have a easy fix but no such luck. I came across multiple websites stating the radio in this vehicle tends to be problematic so perhaps I'm one of those vehicles.

 

[TJBaker57]

I have actually removed my Bose 6 disc CD player and opened it up to explore the CD player issues. Ultimately I found all it needed was a small amount of proper lubrication in just the right spot or two.

However, this was a MAJOR undertaking, one of the most delicate and intricate mechanisms I have ever worked on. This includes disassembly and reassembly of things like 35mm cameras and zoom lenses and the like.

I imagine all 20 year old CD players have old and dried out lubrication. But of course this has nothing to do with inoperative speakers.

I once swapped in a used BCM on my truck, just for the experience, to see how it worked. Naturally the radio displayed "locked" after I did this. After a security relearn and a bit of experimenting I swapped my original BCM back in since I had seen what I wanted to see.

At some point I used my Tech 2 to do a VIN relearn on the radio. It was not a big issue to get the radio back in operation. So if you decide to try another GM original radio anyone nearby with a Tech 2 should have no issue doing the VIN relearn.

The scrap yard I use sells used Radios with CD or media players for about $30. I have one from a 2005 or 2006 I think that I got just to add to my collection of modules for experimentation.

 

[Mooseman]

I would bet that your rear speakers are blown. It's a common failure part. Check them first before condemning the radio. Failures of the radio are few and far between, except for the CD unit.

 

[Elizabetty]

I would bet that your rear speakers are blown. It's a common failure part. Check them first before condemning the radio. Failures of the radio are few and far between, except for the CD unit.

Definitely looking into the common rear speaker issue first. Here's a really dumb question LOL.... When the radio is reset from fuse disconnect for example or even with the battery fully disconnected for an extended amount of time, why don't my personal music preferences reset? The clock resets as expected but for example, where I set bass and treble never resets. I'm assuming there is an internal memory of some sort that causes this but I've had my battery fully disconnected for a long extended amount of time and all I ever have to do is reset the clock.

 

[Mooseman]

IIRC, if the radio or battery is disconnected for an extended period of time, it loses everything. That's why in a lot of the procedures in the manual calls for saving radio presets prior to disconnecting the battery and restoring them after using the Tech 2.

 

[Elizabetty]

IIRC, if the radio or battery is disconnected for an extended period of time, it loses everything. That's why in a lot of the procedures in the manual calls for saving radio presets prior to disconnecting the battery and restoring them after using the Tech 2.

That's why I am confused. I've had my battery fully disconnected, both terminals, for hours at a time and when I get back in, my radio presets for listening mode as far as bass and treble never reset. If I recall correctly, my station presets are also saved. Only the clock resets. I guess maybe I'm lucky LOL but more realistically I'd like to understand why loss of power isn't resetting my radio.

 

[Mooseman]

Maybe some have better memory retention or an internal battery to keep the memory alive. Clocks are another story though. That I've never seen being right after a disconnect. Might depend on year/model.

 

[budwich]

maybe those settngs aren't in that kind of memory

 

[Elizabetty]

Whatever it is, I'll take it. I have no problems resetting a clock. Everything else saves and that's the stuff that's a pain in the butt. Finally a bright spot on this rust bucket I've taken such a liking to....lol